Hi, We are mounting and traversing one backup of a VM with XFS filesystem. Sometimes during traversing, the process goes into D state and can not be killed. Eventually system needs to IPMI rebooted. This happens once in 100 times.
This VM backup is kept on NFS storage. So we first do NFS mounting. Then do loopback mount of the partition which contain XFS. After that we traverse the file system, but this traversing is not necessarily multi threaded (We have seen the issue in both single-threaded and multi-threaded traversal) I see a similar problem reported here: https://access.redhat.com/solutions/2456711 The resolution given here is to upgrade the linux kernel to kernel-3.10.0-514.el7 RHSA-2016-2574 RHEL7.3. Upgrading the kernel may not be possible for us. Is there any patch/patches that we can apply to fix this issue. One more thread here says that this issue is fixed only in the above kernel version. It is seen in previous as well as later versions. https://bugs.centos.org/view.php?id=13843&history=1 Is there anyway to reproduce this problem. All our efforts to reproduce this issue have not succeeded. Please help me know if any more debugging can be done. Thanks, Dinesh Kernel version of source VM, whose backup is taken. root@web-2318 ~]# uname -a Linux web-2318.website.oxilion.nl 3.10.0-514.26.2.el7.x86_64 #1 SMP Tue Jul 4 15:04:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux Kernel version of the machine where backup is mounted and traversed. 3.10.0-327.22.2.el7.x86_64 #1 SMP Tue Jul 5 12:41:09 PDT 2016 x86_64 x86_64 x86_64 GNU/Linux Mon Dec 4 21:08:21 2017] yoda_exec D 0000000000000000 0 48948 48938 0x00000000 [Mon Dec 4 21:08:21 2017] ffff8801052437b0 0000000000000086 ffff88000aa02e00 ffff880105243fd8 [Mon Dec 4 21:08:21 2017] ffff880105243fd8 ffff880105243fd8 ffff88000aa02e00 ffff88010521e730 [Mon Dec 4 21:08:21 2017] 7fffffffffffffff ffff88000aa02e00 0000000000000002 0000000000000000 [Mon Dec 4 21:08:21 2017] Call Trace: [Mon Dec 4 21:08:21 2017] [<ffffffff8163b7f9>] schedule+0x29/0x70 [Mon Dec 4 21:08:21 2017] [<ffffffff816394e9>] schedule_timeout+0x209/0x2d0 [Mon Dec 4 21:08:21 2017] [<ffffffffa07a2e67>] ? xfs_iext_bno_to_ext+0xa7/0x1a0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffff8163ab22>] __down_common+0xd2/0x14a [Mon Dec 4 21:08:21 2017] [<ffffffffa07b00cd>] ? _xfs_buf_find+0x16d/0x2c0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffff8163abb7>] __down+0x1d/0x1f [Mon Dec 4 21:08:21 2017] [<ffffffff810ab921>] down+0x41/0x50 [Mon Dec 4 21:08:21 2017] [<ffffffffa07afecc>] xfs_buf_lock+0x3c/0xd0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa07b00cd>] _xfs_buf_find+0x16d/0x2c0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa07b024a>] xfs_buf_get_map+0x2a/0x180 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa07b0d2c>] xfs_buf_read_map+0x2c/0x140 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa07dd829>] xfs_trans_read_buf_map+0x199/0x400 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa0790204>] xfs_da_read_buf+0xd4/0x100 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa0790253>] xfs_da3_node_read+0x23/0xd0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffff811c153a>] ? kmem_cache_alloc+0x1ba/0x1d0 [Mon Dec 4 21:08:21 2017] [<ffffffffa07914ce>] xfs_da3_node_lookup_int+0x6e/0x2f0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa079bded>] xfs_dir2_node_lookup+0x4d/0x170 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa07937b5>] xfs_dir_lookup+0x195/0x1b0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa07c1bb6>] xfs_lookup+0x66/0x110 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffffa07bea0b>] xfs_vn_lookup+0x7b/0xd0 [xfs] [Mon Dec 4 21:08:21 2017] [<ffffffff811e8cad>] lookup_real+0x1d/0x50 [Mon Dec 4 21:08:21 2017] [<ffffffff811e9622>] __lookup_hash+0x42/0x60 [Mon Dec 4 21:08:21 2017] [<ffffffff8163342b>] lookup_slow+0x42/0xa7 [Mon Dec 4 21:08:21 2017] [<ffffffff811ee4f3>] path_lookupat+0x773/0x7a0 [Mon Dec 4 21:08:21 2017] [<ffffffff81186f6a>] ? kvfree+0x2a/0x40 [Mon Dec 4 21:08:21 2017] [<ffffffff811c13b5>] ? kmem_cache_alloc+0x35/0x1d0 [Mon Dec 4 21:08:21 2017] [<ffffffff811ef1ef>] ? getname_flags+0x4f/0x1a0 [Mon Dec 4 21:08:21 2017] [<ffffffff811ee54b>] filename_lookup+0x2b/0xc0 [Mon Dec 4 21:08:21 2017] [<ffffffff811f0317>] user_path_at_empty+0x67/0xc0 [Mon Dec 4 21:08:21 2017] [<ffffffff811f0381>] user_path_at+0x11/0x20 [Mon Dec 4 21:08:21 2017] [<ffffffff811e3bc3>] vfs_fstatat+0x63/0xc0 [Mon Dec 4 21:08:21 2017] [<ffffffff811e4191>] SYSC_newlstat+0x31/0x60 [Mon Dec 4 21:08:21 2017] [<ffffffff811f27fc>] ? vfs_readdir+0x8c/0xe0 [Mon Dec 4 21:08:21 2017] [<ffffffff811f2cad>] ? SyS_getdents+0xfd/0x120 [Mon Dec 4 21:08:21 2017] [<ffffffff811e441e>] SyS_newlstat+0xe/0x10 [Mon Dec 4 21:08:21 2017] [<ffffffff81646889>] system_call_fastpath+0x16/0x1b
